1. Field of the Invention
The present invention relates to a device for blowing and spraying upper and lower dies used in a forging press, particularly in high speed automatic presses such as transfer presses.
2. Prior Arts
Among various types of forging presses, in certain types used for manufacturing efficiently a large amount of forged products at high speed such as transfer presses provided with a lifting beam, it has been conventionally required for dies held between upper and lower die holders to be cooled, cleaned and lubricated for the purpose of retaining a certain product quality and/or preventing the dies from being deformed. That is, it is an essential requirement of smooth operation that a blowing and spraying assembly is moved into a gap of the die space formed just after moving a slide up and securing the upper die holder, so that a fluid may be sprayed or jetted from a jet nozzle to the surface of the dies thereby blowing scales away, cooling and lubricating the die surface. In this respect, various methods for moving the blowing and spraying assembly have been heretofore proposed and actually put into practical use. Under the background of recent demand for high speed operation of forging presses and the need to increase the frequency of moving the slide up and down, the construction of the blowing and spraying assembly to move quickly in conformity with the timing of the up and down movement of the slide has become one of the technical problems to be solved.
Several attempts have been proposed in order to solve this problem. The Japanese Laid-Open Patent Publication (unexamined) No. 54-124867 discloses a mechanism for moving a blowing and spraying assembly in and away from a die space of a forging press by operating a crank arm, and in which, as shown in FIG. 6 herein, a quadric linkage 5a is connected to a crank chain 101 mounted on a bed, and a blowing and spraying assembly 6a is connected to the linkage.
The U.S. Pat. No. 4,520,643 discloses a construction in which, as shown in FIG. 7 herein, movement of a blowing and spraying assembly is not dependent upon a separate drive source, but a driving force receiving directly from a lifting motion of a slide 11b by an angle lever 2b of a quadric link 5b, which pivots the blowing and spraying assembly 6b.
The Japanese Laid-Open Utility Model Publication (unexamined) No. 56-80933 discloses a construction in which, to form a drive source for driving a blowing assembly, a slide is not employed, but one end of a crank lever is engaged with a cam mounted on a transfer beam and the blowing and spraying assembly is engaged with another end of the lever, whereby movement of the beam is associated with movement of the blowing and spraying assembly.
In any of the above-mentioned prior art device, the blowing and spraying assembly is automatically moved forward and backward either directly in association with operation of the forging press or through a separate drive source, whereby the die is cooled and lubricated synchronously with the opening and closing of the die space.
It may be said that any of the above-mentioned prior art devices succeeds in overcoming the inefficiency of performing the required cooling, cleaning and lubrication of the die manually by an operator using a hand pistol spray or the like, thus mechanizing a series of operations and improving working performance.
In this regard, it is a matter of course that dimensions of every part of a forging press are determined on the basis of certain design elements, and operation of the press is achieved in accordance with functions determined by those dimensions. For example, the stroke of moving the slide up and down is constant or fixed for one forging press and never changed unless otherwise any special structural change is introduced. It is, however, to be noted that products to be manufactured by one forging press are not always fixed, but usually involve manufacturing several different types of products even in a working day. As a result, a die as well as a die holder holding the die is obliged to be replaced to meet each of the different types of products. Since the shape and dimensions of products are largely different, i.e., spherical, square, semicircular, round or square bar-like, etc., the die for forming such products as well as the die holder thereof must be changed to be square, round or rectangular in their mounting face. Thus, it is usually arranged that, though dimensions and shape of a slide of one forging press are fixed, the size of a die holder attached to the lower end of the press is varied enough to meet the different sizes of the products.
As mentioned above, the dimensions of the respective members as well as the specification of the combination thereof are already fixed at the design stage of a forging press before manufacturing thereof. Therefore, when driving a blowing and spraying assembly for interlocking with a slide or transfer beam which merely repeats a predetermined operation, the blowing and Spraying assembly will also merely repeat a predetermined locus. Since the shape of the die and the die holder subject to blowing and spraying may vary largely as mentioned above, there is a case wherein entire surface area of a die which actually needs cooling, cleaning and lubrication is not always completely cooled, cleaned and lubricated through such a limited predetermined locus of the blowing and spraying assembly, but a certain dead angle where cooling, cleaning and lubrication is not performed may take place. Moreover, there is a possibility that, with a stroke of a blowing and spraying assembly which was predetermined as the greatest common measure, a part of a movable member such as a the first lever of a linkage collides with a die holder, if large size die holders are attached to a slide. To prevent such a collision, the size of the die holders and/or the size of the products may be obliged to be restricted.
In any of the foreging prior art devices, when it is intended to change a predetermined stroke of a blowing and spraying assembly, a problem exists in that the incorporated quadric linkage itself must be essentially changed, which means that the entire device for moving the blowing and spraying assembly must be essentially rearranged, resulting in a considerable cost far from an economically acceptable solution.